Research will involve continuation of the recapture program in Guatemala to follow movements of the 2600 bats banded to date. To extend our earlier serological studies to better understand regional and yearly variations in the extent of involvement of bats in VE virus cycles, larger series of plasmas will be collected from nonbanded individuals captured at major banding stations and at, and distant from, La Avellana. Laboratory work will involve comparative studies of 3 isolates of VE virus from bats made in Cornell laboratories in terms of virulence and serological characters. With the documentation of the involvement of bats in endemic VE virus cycles in Guatemala and experimental evidence of the potential bats have as amplifying hosts, it is proposed to extend field studies to northern Venezuela where within a few hours radius of Maracaibo are regions of endemic VE virus activity and the Guajira Pennisula, famous as the epicenter of periodic epizootics/epidemics. A survey trip is proposed to collect plasmas from 200-300 bats from each area to initiate studies of the possible role of bats in regions of epizootic VE virus activity.